LOS ANGELES  Guy Pearce didn't choose the film Two Brothers so much as it chose him.

Director Jean-Jacques Annaud tried to ensure the 30 cats used in the film were in a comfortable setting.

Universal Studios via AP

Pearce had promised himself a year off after a hectic 2002, in which he starred in four films. He and his wife, Kate Mestitz, took a six-month vacation in Cambodia only to discover that their 15-year-old cat, Dudley, had died while they were away.

On his return, he found a script in the mail about two tiger cubs, to be filmed in Cambodia.

"How could I not take it?" he says. "The story felt very close to my own experience, and I loved the message about respecting these amazing animals and the world where they live."

Two Brothers, which opens today, might be the nature-friendly film of the year. Director Jean-Jacques Annaud, who made his name with the 1988 hit The Bear, built a zoo for Two Brothers— for the humans. He built cages for the actors, camera crews and himself. They locked themselves in the chicken-wire cells and filmed the tigers, which ran relatively free.

"It put the cats in a more natural, comfortable setting," Pearce says. "But more important, you spend nine months on a movie like this and you begin to understand what it must be like to live in a cage. It's pretty horrifying."

That theme plays throughout Two Brothers, in which Pearce plays Aidan McRory, a big-game hunter who learns to appreciate the animals after killing their father. (Related story: Dual personalities in Two Brothers)

Annaud says he nearly made a tiger film 16 years ago, when he was trying to choose a creature to star in his story about an animal surviving in the wild without a mother. He chose a bear but knew one day he would return to an animal film that would star tigers.

The tiger characters, Kumal and Sangha — which were played by about 30 trained cats — take top billing in the film's opening credits.

"Every morning, I'd think to myself, 'How are we going to get these animals to do this?' " Annaud says. "And every night, I'd think they'd performed a miracle."

Annaud's crews penned off stretches of jungle, sometimes in excess of a square mile, to allow the tigers to grow comfortable in the setting. The scope of the set occasionally caused delays — handlers could not find the stars.

No animals were hurt during filming, Annaud says. But humans had a couple of frightening close calls. Pearce and Annaud walked on set to meet the animals and entered a cage with several crew members. One of the more boisterous cats leaped onto the cage.

"He was just playing, like any big cat," Annaud says. "But when he was putting his paws in the cage, he started shredding it like paper. You suddenly realized what these animals could do if they wanted to. So we kept them well fed."

Two Brothers, which partnered with the World Wildlife Fund, ends with the caution that the tiger population has plummeted from 100,000 at the beginning of the 20th century to about 5,000 today.

"I hope people ... walk away with the kind of appreciation I gained for them," Pearce says.